Communication system



Patented- June 16, 1936 UNiTED STATES atlases oornuomoa'rrou srs'ruluBarry W. Johnson, Cedar-Rapids, Iowa, assignor to The Turner Company,Cedar Rapids, Iowa,

a corporation of Iowa Application July 1, 1935, Serial No. 29,288

5 Claims. (on. 179-1) My invention relates in general to electricalsound communication systems and it has particular relation to electricalsound communication systems in which two or more stations are 5 employedsuchas in communication between omces and the like and in which theoperator may be at several feet from the transmitting and receivingelement or elements of the respective stations.

Communication systems constructed in accordance with the usual practiceand with which I am familiar have had certain defects. In the devicesknownto the art in which two or more stations for transmitting orreceiving conversation are employed, and in which, during the use of thesystem, one station might be considered the sending station and theother the receiving station, it has been impossible for the operator atthe receiving station to interrupt the operator at the sending stationwhile the operator at the sending station is talking.

For instance, it is sometimes desirable to use a communication system ofthis nature for dictation purposes. It is usually the practice after thecompletion of the dictation that the person receiving the dictationrepeat the material dictated back to the originator for correction. Itwould be very desirable if the one who has dictated the material could,at will, interrupt the operator reading the material for corrections. Inthe devices known to the art and with which I am familiar, the operatorwho is receiving cannot interrupt the operator who is transmitting untilthe second operator is finished.

It is accordingly a general object of my invention to provide anelectrical sound communication system in which a plurality of stationsare employed, any of which may both transmit and receive. I

A more specific object of my invention is to provide an electrical soundcommunication system in which the operator at one station may cut in orinterrupt the operator at the other the system.

According to my invention, in an electrical sound communication systememploying two or more stations, means are provided in the form of anelectrical circuit bywhich the operator at any one station may cut in onthe operator at a second station while the second operator .is talkingover the system. In most sound communication systems of this nature itis possible for only one person to talk at one time over thesystem. If,for instance, an operator at one station is dictating to an operator ata second stationand he calls upon the operator at the second station toread back what he has dictated, then in the ordinary system, if thefirst operator wishes to make a correction, he must wait till the secondoperator station while the second operator is talking on has finishedtalking before he'can do so. With a system constructed according to myinvention the first operator will be able to "cut in" on the secondoperator whenever he so desires.

The novel features that I consider characteristic of my invention areset forthwith particularity in the appended claims. The inventionitself, however, both as to its organization and its method ofoperation, together with additional objects and advantages thereof, willbest be understood from'the following description of a specificembodiment and read in connection with accompanying drawing in whichThe-single figure is a schematic diagram of an electrical soundcommunication system constructed in accordance with the vention. I

The electrical sound communication system shownin the figure :includestwo stations, indicated generally at it and it, each having a soundresponsive unit which may be used either as a transmitter or a receiver.The sound responsive units indicated at it and ii comprise or arecomprised of diaphragms iiia and Ma and coils it?) and lib which aregrounded, as indicated at i2 and i3. 1

The two stations are electrically interconnected,

- by means hereinafter described, to an amplifying circuit indicatedgenerally at it and comprising an input connection iii, an amplifyingprinciples of my in-' tube ill, a. power source it, and an outputtransformer i9. It is evident, in a communication system of this naturein which the same sound responsive. unit is used to convert the soundwaves made by the voice into electrical impulses and also to reconvertthe electrical impulses into sound waves, that some means must beemployed to change a particular sound responsive unit from the re--ceiving condition to the transmitting condition and back. This isaccomplished, in my invention, by the manually operated switchesindicated gen-- erally at 25 and 22. I

The switch indicated at 22, however, differs from the switch shown at 2iin that the switch 22 is a double-pole, double-throw switch, the purposeof which is to enable the operator at station it to cut in on theoperator at iiwhenever the operator at E8 so desires.

amplifying tube H, the primary winding of coil it, power supply it, andground 20. .This amplifying circuit increases the intensity of theelectrical impulses impressed on the circuit from the transmitting unitsand in the primary coil of former I9 are picked up in the secondary coilof the. output transformer I9 and transmitted through conductor 27,conductor 28, switch 2| and the coil lib of the sound responsive unitII.

When the system operates on this circuit the vibrations of the voiceimpressed on the sound responsive unit at station I0 are converted intoelectrical impulses through the agency of the diaphragm lila and coilIllb of the unit Ill. The electrical impulses are transmitted throughthe circuit previously described and are reconverted into sound waves atstation I I through the agency of the coil lib and the diaphragm Ila. ofthe sound responsive unit at the station I I.

when the operator at In is finished speaking he releases the switch key23. If the operator at ii wishes to speak over the system he thendepresses the switch key 29 of switch 2|, as indicated by the dottedlines. This operation completes a circuit through the coil I lb of thesound responsive unit I I, through conductor 3|, through the switchblade 32, the conductor 33, the conductor 26, through the inputconnection ii of the amplifying circuit Il, through theamplifyingcircuit I4, from the secondary of the output transformer I9 through theconductor 21, the switch 22, through the conductor 24, and the coil Illbofthe sound responsive unit I0. When the system is operating on thiscircuit, then the vibrations of the voice impressed on the soundresponsive unit at station II are converted into electrical impulsesthrough the agency. of diaphragm Ila and coil ill; of the soundresponsive unit II. These electrical impulses are transmitted throughthe aforegoing circuit and are reconverted into sound waves at stationIll through theagency of the coil Illb and diaphragm Illa of thesoundresponsive-unit at the station Ill.

However, the operator at station Ill may interrupt the conversation ofthe operator at II atwlll by depressing the switch key 23 to theposition indicated in dotted lines. If the operator at Ill depresses thekey 23 during the period when the operator at II is talking and isholding the switch key of switch 2| in the depressed position shown inthe dotted lines, then the circuit through the coil IIb and conductor 3|to the input sideof the amplifying circuit is broken at the switch 22.At the same time a circuit is formed'from coil Illb of the soundresponsive unit at Ill, through the conductor 24, the conductor 26, theamplifying-circuit I, the conductor 21, the switch blade 32, theconductor 3|, the

' switch key 29, and the coil III) of the sound responsive unit at ll.Therefore, in this manner, the operator at Ill may interrupt theconversation of the operator at II, whenever he so desires and may thusplace station in receiving condition and talk to the operator at II. Itis apparent that the operator at I0 may talk over the system whether theoperator at II holds the switch key in the position shown by thedottedlines or in the position shown in solid lines.

It is apparent, therefore, that my invention provides a simpletwo-station or plural station electrical sound communication system thatwill have varied uses and will be particularly useful for communicationbetween offices and the like.

operator at another station at will. Thus, time will be saved, as forinstance in the correction of messages or material dictated over thesystem 5 andethenrepeated back to the originator. 1 7

Although I have shown and described a certain specific embodiment of myinvention,'1 am fully aware that many modifications thereof arepossible. My invention, therefore, is not to be 10 restricted exceptinsofar as is necessitated'by the prior art and by the spirit of'theappended claims- I claim as my invention: i 1. In an electricalcommunication system, a plurality of stations each having transmitting15 and receiving means, a circuit for connecting the stations, thecircuit having input and output connections, means for selectivelyconnecting the input or the output of the connecting circuit to one ofthe stations for transmitting and receiving respectively, and othermeans at one of the other stations adapted to'break the circuit at thefirst station to change it from transmitting to receiving when it is inthe transmitting condi- 25 tion.

2. In an electrical communication system, a plurality of stations, eachhaving transmitting and sending means, an amplifying circuit connectingthe stations, the amplifyingcircuit having input and outputconnections,- a manually 30 operable two-way switch for selectivelyconnecting the input or the output of the amplifying circuit to one ofthe stations, and a manually operable double-pole, double-throw switchat one of the other stations adapted to break the circuit at .the firststation to change it from transmitting to receiving condition when 'itis in the transmitting condition.

-3. In an electrical communication system employing a plurality ofstations, a connecting clrcuit for connecting the stations having inputand output connections, means at one of the stations for selectivelyconnecting the station to the input or the output of the connectingcircuit, and means at the other station for changing the 45 polarity ofthe connecting means at the first sta-v tion to change its condition.

4. In an electrical communication system em-' ploying a plurality ofstations, an amplifying circuit disposed with its connections betweenthe 50 stations having input and output connections, a two-way switch atone of the stations for selectively connecting the stations to the inputor the output of the amplifying circuit, and a doublepole, double-throwswitch at the other station for changing the polarity of the connectingmeans at the first station to change its condition.

5. In an electrical communication system iiicluding at least twostations, conductors forcon- 6o necting the stations, an amplifiercircuit comprising a tube power supply and output transformer, switchmeans for connecting the filament. or cathode and grid of the tubeselectively to one or-the other of the stations to place them intransmitting condition and the said switch means also being arranged toconnect the other station to the secondary of th output transformer toplace it in receiving condition, and other switch means at one of thestations to reverse the polarity of the conductors to change the otherstation n HARRY w. JOHNSON.

